Output Variant in ALV table

I have this requirement where I am presenting the output (say 15 columns) in ALV table in my webdynpro ABAP app.

I have (say three) users who need some of these fields. Each person's requirement is distinct.

e.g User A needs 1 to 5 fields

User B needs 6 to 10 and

User C needs 11 to 15 fields.

Now, when I give them the report each one will create a user variant (or a user defined view, as you'd normally call it) and would like to see only the relevant fields. So they do that using the Settings link at the top right hand side of the ALV table.

Now, there is a custom link that says 'Export to Excel' which I created. Each one of these users want to export only the required and relevant list from the output.

Can anyone help me as to how can I read, at runtime, which 'user defined view' did the user select so that I could download the same set of fields in the Excel Output.

I know there has to be a way to read what 'user view' did the user select - its just that I don't know it yet...!